The disclosure concerns a digital printer for printing to a recording medium with toner particles that are applied with the aid of a liquid developer, in particular a high-speed printer for printing to web-shaped or sheet-shaped recording media.
In such digital printers, a latent charge image of a charge image carrier is inked by means of electrophoresis, with the aid of a liquid developer. The toner image that is created in such a manner is transferred indirectly (via a transfer element) or directly to the recording medium. The liquid developer has toner particles and carrier fluid in a desired ratio. Mineral oil is advantageously used as carrier fluid. In order to provide the toner particles with an electrostatic charge, charge carrier substances are added to the liquid developer. Further additives are additionally added, for example, in order to achieve the desired viscosity or a desired drying behavior of the liquid developer.
Such digital printers have long been known, for example from DE 10 2010 015 985 A1, DE 10 2008 048 256 A1 or DE 10 2009 060 334 A1.
To ink the charge images on the charge image carrier, liquid developer is directed past the charge image carrier by a developer station. The developer station has a developer element (for example a developer roller) that directs the liquid developer past the charge image carrier; a feed system that feeds the liquid developer to the developer roller; and a cleaning unit that cleans off the residual liquid developer remaining on the developer roller after the inking of the charge images on the charge image carrier. The cleaning unit provides, for example, a cleaning roller that removes the residual liquid developer from the developer roller. An electric field thereby exists between developer roller and cleaning roller that promotes the transfer of the residual liquid developer, for example. The residual liquid developer can be scraped off the cleaning roller by a blade. No residual toner should thereby remain on the cleaning roller, since otherwise this could arrive at the developer roller again.
Developer stations with such cleaning units are known from the documents DE 10 2010 008 211 A1, DE 10 2004 032 922 A1 or DE 10 2009 005 371 A1, for example. Furthermore, given a rotation printing machine (DE 299 18 488 U1) it is known to arrange a cleaning blade system at a coating roller, which cleaning blade system comprises a working blade and a sealing blade, wherein the chamber that is thereby formed is filled with a cleaning fluid via which the coating roller is cleaned of contaminants. An ultrasonic vibration system in the chamber assists with the cleaning.